Seating unit with adjustable lumbar device
A seating unit includes a back support with a perimeter frame defining an opening, and a plurality of resilient members spanning the opening. An upholstery cover extends over and covers the resilient members and a front of the perimeter frame. A bow-tie-shaped lumbar device is positioned between the cover and sides of the perimeter frame for vertical adjustment. The lumbar device includes a body with end sections defining a greater dimension than a middle of the body. Upper and lower edges of the end sections are thin and serve to wedgingly slip between the cover and the resilient members in a manner leading the middle over irregular surfaces between the resilient members. A thick area between the upper and lower edges causes a change in lumbar support force and shape as the lumbar device is adjusted. Handles are attached to the body by stretchable fabric.
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This application is a continuation-in-part of co-assigned co-invented application Ser. No. 10/792,309, filed Mar. 3, 2004, entitled COMBINED TENSION AND BACK STOP FUNCTION FOR SEATING UNIT now U.S. Pat. No. 6,932,430, which is a continuation-in-part of Ser. No. 10/455,076, filed Jun. 5, 2003, entitled COMBINED TENSION AND BACK STOP FUNCTION FOR SEATING UNIT now U.S. Pat. No. 6,880,886, the entire contents of which are incorporated herein in their entirety.
BACKGROUNDThe present invention relates to adjustable lumbar devices for seating units.
Modern chairs and seating units are often provided with adjustable lumbar devices to allow the chair's back to be adjusted for different amounts of lumbar support, as required and desired by different users. However, new lumbar devices are desired that are simpler to manufacture and assemble, and that include less components, lower cost components, and components that function more effectively, and that also provide new visually interesting appearances.
Recently, a new back support was designed having flexible resilient wires extended across an open interior of a perimeter frame. See application Ser. No. 10/792,309, filed Mar. 3, 2004, entitled COMBINED TENSION AND BACK STOP FUNCTION FOR SEATING UNIT, which is incorporated in is entirety by reference. The flexible resilient wires provide excellent ergonomic support to a seated user. However, the wires tend to flex in a manner that reduces the ability of a lumbar panel to slide smoothly up and over each wire during vertical adjustment. A lumbar device is desired that slides more fluidly and smoothly between adjusted positions, yet that is secure in its selected position and effective in its function.
Thus, an improved lumbar device having the aforementioned advantages and solving the aforementioned problems is desired.
SUMMARY OF THE PRESENT INVENTIONIn one aspect of the present invention, a seating unit includes a back support, a back cover located on a front surface of the back support but separated from the back support in a lumbar area of the back cover, and a lumbar device adjustably positioned between the back support and the back cover. The lumbar device is selectively moveable to change a shape of the back cover in the lumbar area. The lumbar device includes a unitary sheet with first panel-like wall portions formed to define a first surface and second panel-like wall portions formed to define a second surface. Third wall portions extend between the first and second wall portions to define space therebetween. The first and second wall portions are configured to slidingly engage the front surface of the back support and a rear surface of the back cover, respectively. By this arrangement, vertical movement of the lumbar device causes a shape change of the back cover for providing improved lumbar support to a seated user.
In another aspect of the present invention, a lumbar device is provided for a seating unit, where the seating unit includes a back with a front surface for supporting a seated user. A lumbar device is adjustably positioned on the back for selectively varying a shape of the back in a lumbar area. The lumbar device includes a unitary sheet of generally uniform thickness. The sheet is thermoformed to have first wall portions formed to define a first surface and second wall portions formed to define a second surface. Third wall portions extend between the first and second wall portions to define space therebetween. By this arrangement, vertical movement of the lumbar device causes a shape change of the back for providing improved lumbar support to a seated user. In a narrower form, the thermoformed sheet includes wedged-shaped upper and lower leading edges.
In another aspect of the present invention, a seating unit includes a back support, a back cover, and a lumbar device. The back cover is located on a front surface of the back support but separable therefrom at least in a lumbar area of the back cover. The lumbar device is adjustably positioned between the back support and the back cover. The lumbar device includes a shape-changing member for changing a shape of the lumbar area during vertical adjustment. Handles are provided that track along edges of the back support. Stretchable elastic material connects the handles to respective ends of the shape-changing member. By this arrangement, vertical movement of the lumbar device causes a shape change of the back cover for providing improved lumbar support to a seated user.
In another aspect of the present invention, a seating unit includes a back support, a back cover located on a front surface of the back support but separable therefrom at least in a lumbar area of the back cover, and a lumbar device adjustably positioned between the back support and the back cover. The lumbar device includes a flexible sheet configured to slidingly engage the front surface of the back support and a rear surface of the back cover, respectively. The lumbar device further includes a wire that extends across and supports the flexible sheet, and still further includes handles that track along edges of the back support and yet still further includes stretchable material that connects the handles to respective ends of the wire. Thus, vertical movement of the lumbar device causes a shape change of the back cover for providing improved lumbar support to a seated user.
In another aspect of the present invention, a seating unit includes a back support having side frame members and horizontally extending resilient members defining irregularities in a vertical direction in a lumbar area of the back support. A back cover is provided that is shaped to cover at least a front of the side frame members. A lumbar device is positioned between the back cover and the resilient members for affecting lumbar support. The lumbar deice has a body with end sections connected by a middle section. The end sections have a larger dimension than the middle section and are shaped to guide edges of the middle section over the irregularities as the lumbar device is vertically adjusted.
These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.
A seating unit 20 (
The perimeter frame 24 (
The illustrated resilient members 26 are spring steel wires having round cross sections. However, it is contemplated that a scope of the present invention also includes other resilient support members, such as flat springs, non-metal plastic springs, springs made from composite materials, and other resilient support means.
It is contemplated that the present cover 27 (
The lumber device 28 (
The body 29 (
The outboard ends of the body 29 (
The handles 35 (
Assembly of the lumbar device 28 (
The lumbar device 427D (
Unlike prior art lumbar devices, it is contemplated that the front and rear thin panels 681 and 682 are as thin as possible and are surprisingly flexible, so that the lumbar support comes from the active flexing of the wire 680, rather than from a stiff flat part. Thus, the lumbar support provided is very much like the support provided by the wires 78D in “comfort surface” of the back 23D. As a result, the lumbar support comes from the increase in force versus displacement curve provided (i.e. the wire 680 of the lumbar device supplements the wires 78D of the back 23D) . . . instead of the increased lumbar support coming only from a forced shape change in the lumbar area of the back 23D. Nonetheless, it is contemplated that increased lumbar support can come from both a lumbar shape change and also an increased lumbar support force curve.
The wire 680 is able to flex and move within and between the panels 681 and 682, and the ends 685 of the wire 680 extend outward from ends of the panels 681 and 682. Handles 683 include a thin body 688 with a U-shaped cavity 689 for receiving the ends 685. A handle 690 is attached to an end of components 680, 681, 682, and extends outward from them to form a grip to facilitate adjustment of the lumbar device 427D that can be grasped from a side of the chair 20D. The wire 680 can be snapped into position or a second tab or a clip 691 can be provided to loosely retain the wire 680 slidably within the U-shaped cavity 689. Advantageously, one or both sides of the lumbar device 427D can be adjusted, so that an optimal comfortable support can be obtained. The lumbar device 427D is held in place by the tension of the back covering 656, which, due to the curvature of the back, causes tension between the back covering 656 and the back frame 667.
It is contemplated that the wire loop 680 can be replaced with a flat strip of spring metal or leaf-spring-like plastic member. In fact, the entire lumbar wire 680 and “clam shell” covers 681, 682 could be replaced with a single molding or stamping, with its handles 42 being formed on or attached to ends of the lumbar device.
Another lumbar device 427E (
The lumbar device 427E is positioned under the upholstery back covering and in front of the back frame side sections 71E, with the handles 683E slidably engaging the side section 71E. If the back frame side sections 71E are non-parallel, the sock 682E stretches (or elastically shrinks) to compensate as the lumbar device 427E is moved vertically. The slipperiness of the sock 682E helps the lumbar device 427E slip up and over each successive back wire 78E as the lumbar device 427E is vertically adjusted. The long parallel sections of the wire 684E can be (but do not necessarily need to be) bent to form a slightly bowtie-shaped arrangement, which shape also helps slip up and over each successive wire 78E.
It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.
Claims
1. A seating unit comprising:
- a back support;
- a back cover located on a front surface of the back support but separable therefrom at least in a lumbar area of the back cover; and
- a lumbar device adjustably positioned between the back support and the back cover, the lumbar device including a shape-changing member for changing a shape of the lumbar area during vertical adjustment, and further including handles that track along edges of the back support and still further including a nonmetal stretchable elastic material that connects the handles to respective ends of the shape-changing member, whereby vertical movement of the lumbar device causes a shape change of the back cover for providing improved lumbar support to a seated user.
2. The seating unit defined in claim 1, wherein the lumber device includes a wire attached to the shape-changing member and that extends horizontally across the shape-changing member.
3. The seating unit defined in claim 2, wherein the third wall portions define a groove for receiving the wire and further include friction tabs that snap-attach the wire to the shape-changing member.
4. The seating unit defined in claim 3, wherein the shape-changing member comprises a thermoformed panel.
5. The seating unit defined in claim 4, including handles that are operably connected by stretchable material to ends of the shape-changing member.
6. The seating unit defined in claim 5, wherein the handles slidably engage and track non-parallel edges of the back support.
7. A seating unit comprising:
- a back support;
- a back cover located on a front surface of the back support but separable therefrom at least in a lumbar area of the back cover; and
- a lumbar device adjustably positioned between the back support and the back cover, the lumbar device including a longitudinally, non-stretchable flexible panel configured to slidingly engage the front surface of the back support and a rear surface of the back cover, respectively, and still further including handles that track along edges of the back support and yet still further including stretchable material that connects the handles to respective ends of the the flexible panel, whereby vertical movement of the lumbar device causes a shape change of the back cover for providing improved lumbar support to a seated user.
8. The seating unit defined in claim 7, wherein the flexible panel comprises a thermoformed panel.
9. A seating unit comprising:
- a back support including side frame members and horizontally extending resilient members spaced in a vertical direction in a lumbar area of the back support;
- a back cover shaped to cover at least a front of the side frame members; and
- a lumbar device positioned between the back cover and the resilient members for affecting lumbar support, the lumbar device having a body with end sections connected by a middle section, upper and lower edges of the vertical end sections being relatively thin and defining a larger vertical dimension than the middle section forming wedges and shaped to guide the upper and lower edges of the middle section over the resilient members as the lumbar device is vertically adjusted.
10. The seating unit defined in claim 9, including handles that slidably engage and track non-parallel edges of the back support as the lumbar device is vertically adjusted.
11. The seating unit defined in claim 10, including elastic stretchable sections connecting the handles to the body.
12. The lumbar device defined in claim 9, wherein the resilient members comprise wires.
13. The seating unit defined in claim 9, wherein the body includes upper and lower edges that are curvilinear to define a bow tie shape.
14. The seating unit defined in claim 13, wherein the upper and lower edges are relatively thin and areas therebetween have a thicker dimension.
15. The seating unit defined in claim 9, wherein the body is a flexible plastic panel.
16. The seating unit defined in claim 15, wherein the body is thermoformed to include first walls on a front side and second walls on a rear side and third walls interconnecting the first and second walls, the third walls maintaining a spacing of the first and second walls.
17. The seating unit defined in claim 16, wherein the body includes a groove, and wherein the wire snaps into the groove.
18. The seating unit defined in claim 9, including handles attached to ends of the body.
19. The seating unit defined in claim 18, wherein the handles each includes a grip that engages one of the side frame members and further including stretchable elastic material that connects each grip to an end of the body.
20. The seating unit defined in claim 19, wherein the elastic material is stretched and causes the handle to frictionally engage the side frame members in a manner holding the lumbar device in a selected position.
21. The seating unit defined in claim 9, wherein the lumbar device is visible in the back support.
22. The seating unit defined in claim 9, wherein the lumbar device is visible between the resilient members.
23. The seating unit defined in claim 9, including a handle attached to each end of the body that engages a mating slot in the side frame members.
24. The seating unit defined in claim 9, wherein the body is symmetrical about a vertical centerline and a horizontal centerline.
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Type: Grant
Filed: May 14, 2004
Date of Patent: Aug 29, 2006
Patent Publication Number: 20040245825
Assignee: Steelcase Development Corporation (Caledonia, MI)
Inventors: Robert J Battey (Middleville, MI), Eric Johnson (Hudsonville, MI), Jonathan B. Hadley (Holland, MI), Gordon J. Peterson (Rockford, MI)
Primary Examiner: Rodney B. White
Attorney: Price, Heneveld, Cooper, DeWitt & Litton LLP
Application Number: 10/846,304
International Classification: A47C 3/025 (20060101); A47C 3/026 (20060101);